It's always a good idea to have a very clear justification for your research design and methods before collecting data, but now that you've already done it, you might look to a textbook on mixed methods to reflect on your rationale for the approach you've taken (e.g. see Creswell and Plano Clark, 2017).

Similarly, it would have been a good idea to consider construct validity to some extent before actually administering the questionnaire (e.g. face validity, at least), but perhaps you can go back to the construct(s) you were trying to measure and look more explicitly at whether and how your items measure all aspects of that/those construct(s)?

The lesson learned here, really, is not to jump ahead too quickly to data collection, and to make sure you have your justifications for design and methods fully fleshed-out before proceeding.

It's always a good idea to have a very clear justification for your research design and methods before collecting data, but now that you've already done it, you might look to a textbook on mixed methods to reflect on your rationale for the approach you've taken (e.g. see Creswell and Plano Clark, 2017).

Similarly, it would have been a good idea to consider construct validity to some extent before actually administering the questionnaire (e.g. face validity, at least), but perhaps you can go back to the construct(s) you were trying to measure and look more explicitly at whether and how your items measure all aspects of that/those construct(s)?

The lesson learned here, really, is not to jump ahead too quickly to data collection, and to make sure you have your justifications for design and methods fully fleshed-out before proceeding.

Hi Hossein...

From what I gathered from your description, you're wondering if it is okay to use your questionnaire for the next phase of your study, is that correct?

Anyway, if that's the case, I do believe that it is okay... questionnaire, after all, has to be content specific so respondents can relate to the items. However, the major question here is, do you have the theoretical/conceptual foundation for the questionnaire? When you conducted your interview, what was the theoretical/conceptual foundation you use... or did you even use one? IF you use one, then your questionnaire would be ideally aligned to the theory/concept you used. and IF you didn't use one (aka you conducted an exploratory interview), then you can make your items following the themes/categories you concluded from the interview and as you see fit. Here are the example for both cases:

From those two example, you can see how they are essentially different. But, following the survey phase, both are generally the same. Since you have a questionnaire (and i'm assuming you're going to have numerical data) and you have the data from participants, you can do the statistical analysis to see the construct validity of your questionnaire. Which statistic you use would be depending on what kind of data though. Anyway, point is, you could just determine which one your study is first and then read how that one is usually conducted.

I hope this helps. I'm sorry if this confuses you even more.

to me a questionnaire is very important because it shows your objectives, it shows your hypothesis if you have any, analysis is based on the questionnaire and conclusion. this is because the questionnaire ensure that no stone is left unturned in trying to prove your hypothesis or find out more on a topic.

Even in qualitative data collection, structured tools are necessary to ensure that you exhaust all you wish to get from the respondent or participant.

To me a questionnaire is very important because it shows your objectives, it shows your hypothesis if you have any, analysis is based on the questionnaire and conclusion. this is because the questionnaire ensure that no stone is left unturned in trying to prove your hypothesis or find out more on a topic.

I would like to thank all the researchers who answered my question.

Short answer from my side - and I take a pragmatic philosophical worldview - : no. As long as you can justify an approach based on your research questions (thus how to best answer them), it is fine, if you can not properly justify an approach you should consider an alternative approach that better suits you. Please have a look at the range of potential methods to collect your data. There is observation, video, audio, etc etc etc. Hope I can help.

Hi!

Another option you can use in qualitative research is member-checking. This would entail that interviewed participants are contacted following data analysis and have the opportunity to clarify or confirm your qualitative interpretations of the results related to their particular interview. You can add a section about member-checking in your research methods and how this contributed to the validity of your findings.

Here is an article that you might find helpful about member-checking (or respondant validation): https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118901731.iecrm0149

Qualitative approaches to data collection in research have a subjective nature . Consequently, they are often triangulated to improve the generalizability of the findings. Since the interview requires certain standards to be observed , the credibility of the data collected through the interview should be supplemented by using a questionnaire in order to create a more focused interpretation and conclusion.

Quality inputs.

I too recommend to supplement the questionnaire to add more meaning to the results.

Interview questions should related to the research hypothesis.